Loop-shaped Sling Adapter for use on Buffer Tube Assembly or Rifle Stock

ABSTRACT

A clamping sling attachment is configured for use on a carbine or rifle such as the M4 having it&#39;s a butt stock mounted on a cylindrical proximally projecting buffer tube, where a distal end of the buffer tube is threaded into the rear of the rifle&#39;s receiver. The sling attachment is releasably mountable on the buffer tube as an openable spring-clamp like loop which can be opened enough to go around the buffer tube&#39;s cylindrical outer wall. The sling attachment also has a laterally or transversely projecting sling mount defining a substantially vertical, transverse sling-hook receiving through-bore on one side to which the lower end of a weapon sling is releasably attachable. The buffer tube&#39;s central axis is the same as the sling attachment loop&#39;s central axis and is substantially perpendicular to the sling attachment&#39;s transverse sling-hook receiving through-bore.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM TO PRIORITY

This application claims the benefit of and priority to U.S. provisional patent application No. 61/178,966, filed May 16, 2010, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to slings for weapons and more particularly relates to a sling fitting for a rifle or carbine such as the U.S. M16A2 or M4.

2. Discussion of the Prior Art

Slings are a common accessory used with rifles or carbines such as the M4 (e.g., such as carbine 100, shown in FIG. 1), as well as other types of weapons. The standard AR15 or M16 typically uses a two-point sling, as do most conventional rifles. The “two point” nomenclature refers to a first sling connection near the front of the rifle and a second connection near the rear of the rifle.

A sling must either attach to an existing part of the weapon or the weapon must be adapted to accommodate the sling. Many devices, fittings and systems have been developed to attach slings to weapons. See, for example, U.S. Pat. No. 6,325,258 to Verdugo, et al. (2002); U.S. Pat. No. 6,260,748 to Lindsey (2001); U.S. Pat. No. 5,971,239 to Marable (1998); U.S. Pat. No. 5,848,491 to Biemont (1998); U.S. Pat. No. 5,692,654 to Bell (1997); U.S. Pat. No. 5,3305,540 to Blenk (1994); U.S. Pat. No. 5,075,996 to Llames (1991); U.S. Pat. No. 5,074,069 to Shire (1991); U.S. Pat. No. 4,713,905 to Dupuy (1987); U.S. Pat. No. 4,505,012 to Johnson (1985) and U.S. Pat. No. 149,141 to Metcalfe (1874), all being examples of the prior art.

A single point sling (e.g., 102 or 108 as shown in FIGS. 1 and 2), has a sling which interfaces with the weapon via a pin, hook, clip, or similar fastening device at a selected mounting point (e.g., 103).

The sling of FIG. 2 carries an “HK” style latching hook 110 which is easily opened with one hand. Latching hook 110 is illustrated in detail in FIG. 3.

The designs of FIGS. 1-3 allow connection of a single point sling on M4/AR15/M16 rifles so the rifle to be easily carried in a favorable position which is balanced and handy for quick use. A single point sling is normally positioned more centrally on the rifle and may include a hook or loop which attaches to a vertically slotted connection point, but these kinds of connections, which twist the sling, make certain manipulations awkward for the user.

Another sling attachment, 120 as shown in FIG. 4, includes a “quick-release” style button-actuated single point releasable connection 130, but when used with a sling loop (e.g., as in FIG. 1), the quick release swivel doesn't perform as well as intended. Actual users (e.g., Marines and Soldiers) have reported that, when under duress, the quick release sling swivel is difficult to remove quickly, especially when the sling is under tension and partially covers the release actuating “quick release” button 130. In order to remove the sling, the user is required to execute a pushing and lifting (pulling) movement to release the “quick-release” sling swivel (where the push-then-lift method requires opposing movements which end up fighting each other). In other words, in a life-threatening situation, it is difficult to punch the center release button 130 on a quick release swivel and pull the sling out and away from the rifle.

There is a need, therefore, for a convenient, flexible, inexpensive and unobtrusive system and method for allowing users to attach a single point sling to a weapon such as a rifle or carbine.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to overcome the above mentioned difficulties by providing a convenient, flexible, inexpensive and unobtrusive system and method for allowing users to attach a single point sling to a weapon such as a rifle or carbine.

In accordance with the present invention, a loop-shaped clamping member is configured with a sling receiving transverse member or Boss which provides an ideal sling attachment point. As noted above, a vertically slotted sling connection point gives rise to twisted slings, and that makes for awkward handling. The loop-shaped clamping member of the present invention provides a transversely projecting connection point which is horizontal and so allows the single point sling to hang naturally without a partial twist in the sling. Normally the single point is only connected to the body-side of the user's rifle, when carried.

When compared to the button-actuated sling attachment of FIG. 4, the loop-shaped clamping member of the present invention is more natural, because there is no requirement to execute the pushing and lifting (pulling) movement to release the sling swivel. Instead, the loop-shaped clamping member of the present invention is configured to work well with an HK style hook (with a spring biased safety catch or lever) because the loop-shaped clamping member orients the user's movements in a single direction of movement when releasing a sling. In other words, in a life threatening situation, it is much easier to depress and release a snapped hook from the loop-shaped clamping member than it is to punch the center release button on the quick release swivel while trying to pull away the sling.

In addition, the loop-shaped clamping member of the present invention is readily adjusted for use in a variety of carry positions. For example, a right-handed user can selectively loosen, rotate and tighten the clamping loop of the present invention so that the transversely projecting attachment or Boss has a selected angular orientation between 7 to 10 o'clock (when viewed from the proximal or butt end of a vertically aligned rifle having its muzzle on a substantially horizontal axis). Rotation of the loop-shaped clamping member of the present invention around the buffer tube's central axis (when mounted on the rifle's buffer tube, proximate the locking nut) allows the user to help balance the side-to-side rotation of the rifle with an infinitely adjustable arc of rotation. This allows the right hand shooter to adjust the position of the Loop to fit his/her carrying style and accessory outfit for the rifle (accessories might include flashlight/IR laser/forward hand grip/bipod, etc.—all of which change the balance of the rifle by adding weight at different points). Applicant knows of no other single point connection which is rotationally adjustable in an ergonomically efficient and convenient way. Other sling connections have a fixed rotational orientation (e.g., such as the rear sling fitting shown in US Pat Appl. 2005/0034347, to Verdugo) and all have a right and left hand connection.

The loop-shaped clamping member of the present invention is readily adapted, in the field, to be shooter side or hand specific (because it can be changed from side to side easily—if needed), and this allows the user to adjust of rifle's rotational balance and orientation when hanging.

A left-handed shooter would put the loop-shaped clamping member of the present invention onto the rifle with the opposing back-to-front orientation (or backwards) in order to accommodate left hand use with the same rotational adjustability, where that desired angular orientation is likely to be between 2 to 5 O'clock (when viewed from the proximal or butt end of a vertically aligned rifle having its muzzle on a substantially horizontal axis).

The loop-shaped clamping member of the present invention advantageously utilizes a horizontal connection (not a vertical slot) which helps to dampen the rifle rotation when the user is moving (because the sling loop doesn't move back and forth as it can in the vertical slots of most single point connections).

Installation of the loop-shaped clamping member of the present invention is also much simpler and easier than installation of prior art sling attachments. Normally, when installing a single into a point sling connection on a rifle (e.g., as shown in FIG. 1), the user must remove the upper receiver from the lower receiver and then remove the buffer tube and buffer spring from the upper receiver by loosening the buffer tube locking nut (which requires a specialized tool), and then cautiously monitoring movement of the cover plate which hides 1 of 2 preloaded springs. One spring is located in the forward edge of the buffer tube and retains the buffer in the buffer tube. The buffer tube is threadably engaged in a threaded aperture in the proximal end of the upper receiver and during disassembly, the user has to monitor the buffer tube's number of revolutions of threaded engagement in the lower receiver. Often, even with gunsmiths, one of the detents or springs can flying off and can be lost. This can effectively leave the M4 inoperable. It is very likely that users in the military are attempting this disassembly in the field and so some parts loss is seems inevitable.

The loop-shaped clamping member of the present invention is specifically designed to avoid this problem and allows the user to entirely avoid the process of taking apart the buffer tube assembly when mounting or adjusting a single point sling mount. The loop-shaped clamping member of the present invention is biased like a spring clamp and is flexible, tough and ductile enough to permit significant spreading at the loop opening, and can be deformed or spread to open the loop opening so that it can be placed around a standard buffer tube assembly's cylindrical sidewall. When being installed, loop-shaped clamping member of the present invention is opened or unfastened and the clamp's mating first and second ends are simply spread apart by hand and slipped over the buffer tube/locking nut ring without ever removing anything from the rifle's (e.g., M4 or CAR) butt assembly.

The loop-shaped clamping member of the present invention is configured as a substantially cylindrical spring clamp-like assembly made from a strip of spring steel (or spring-steel like (e.g., 17-4) stainless steel) which is fabricated to be biased in the closed or clamped position, such that a first clamp end is proximate to or abuts a second clamp end when the loop-shaped clamping member of the present invention is at rest, on or off the rifle.

The loop-shaped clamping member of the present invention, when in the normal, closed position defines a cylinder having a central axis and an axial wall height of 0.388 inches and an interior lumen diameter of 1.345 inches. The sidewall thickness of the clamping member is, for most of its length, 35 thousandths (0.035″).

Each of the clamp ends is configured with a transversely projecting flange to receive and engage a threaded fastener in first and second fastener receiving bores. The first end flange's bore is aligned with the second end flange's bore along a fastener axis which is orthogonal to the central axis of the clamp, so that a threaded bolt or screw inserted into and through the bore in the first end flange can be threadably engaged in the bore of the second end flange, to approximate and fasten the clamp ends together. When viewing the clamp assembly from the perspective of the loop-shaped clamp assembly's central axis, with the first and second ends at the bottom, the transversely projecting boss projects in a substantially horizontal direction, meaning that the transverse (sling receiving) boss projects outwardly from the clamp's exterior wall at an azimuth which is 90 degrees or one quarter of the wall's circumference from the nearest (e.g., second end's flange).

As noted above, in use, the first clamp end can be spread apart from the second clamp end, increasing the diameter of the loop, enough to permit the clamp's ends to go around the periphery of and onto the rifle's buffer tube assembly. The clamp is then easily and slidably rotated around the exterior sidewall of the buffer tube assembly, into a desired angular orientation for the user, and then clamped tightly onto the buffer tube assembly where it will no longer permit any axial slip around the buffer tube's exterior sidewall.

Preferably, the loop-shaped clamping member of the present invention is fabricated from a 17-4 stainless alloy and anodized in a black or earth-tone color. The loop-shaped clamping member of the present invention can be installed and removed, adjusted and readjusted literally hundreds of time without fear of failure. It can be installed (if an Allen wrench is close at hand) in less than one minute, and is designed for use with a collapsible AR stock (CAR) rifle or where any buffer tube locking nut or butt extension are exposed on a different style of rifle.

Another method of installation (though more time consuming) is accomplished by pulling out on the CAR length adjustment lever arm (normally the lever is compressed to select the length position setting) and sliding the plastic butt assemble off of the buffer tube. This allows one to install the loop-shaped clamping member of the present invention by simply spreading the loop (not as much as when snapping over the buffer locking nut by itself) and then sliding it down the length of the buffer tube and over the buffer tube-locking nut. Next, the user orients or adjusts the loop-shaped clamping member's transverse boss to the user's desired position and tightens the loop in place (e.g., with an Allen wrench). The AR15/M16's charging handle remains unobstructed and operable with the loop-shaped clamping member in place and positioned appropriately.

The clamp assembly adapted for use with the M4 is also referred to as the “Grunt loop”, and since it is configured to easily and quickly attach to an M4 stock assembly's buffer tube, it is also configured for easy use upon aftermarket CAR15 or M4 compatible buttstock assemblies or “back ends” such as a MAGPUL® aftermarket stock assembly.

While the standard production loop-shaped clamping member is machined from a stainless steel alloy (e.g., 17-4 stainless steel), for corrosive environments (saltwater) the loop-shaped clamping member of the present invention can optionally be made from 316L Stainless Steel, with a Stainless Steel clamping Cap Screw.

Another embodiment for use with the M16A2 uses an oval loop-shaped clamping member, configured for use on the butt-stock of a M16A2. The oval loop-shaped clamping member is configured as an asymmetrical elliptic cylinder-shaped spring clamp-like assembly made from a strip of spring steel (or spring-steel-like (e.g., 17-4) stainless steel) which is fabricated to be biased in the closed or clamped position, such that a first clamp end is proximate to or abuts a second clamp end when the loop-shaped clamping member of the present invention is at rest, on or off the rifle.

The loop-shaped clamping member, when in the normal, closed position defines an asymmetrical elliptic cylinder having a central axis and an axial wall height of 0.375 inches and an interior lumen shaped to encircle and tightly hold the outer peripheral wall of an M16's buttstock, at the narrow front end, proximate the receiver. Each of the clamp ends is configured with a transversely projecting flange to receive and engage a threaded fastener in first and second fastener receiving bores. The first end flange's bore is aligned with the second end flange's bore along a fastener axis which is orthogonal to the central axis of the clamp, so that a threaded bolt or screw inserted into and through the bore in the first end flange can be threadably engaged in the bore of the second end flange, to approximate and fasten the clamp ends together. When viewing the clamp assembly from the perspective of the loop-shaped clamp assembly's central axis, with the first and second ends on the left side, the transversely projecting boss projects in a substantially opposing lateral direction, on the right side, meaning that the transverse (sling receiving) boss projects outwardly from the clamp's exterior wall at an azimuth which is nearly on the opposite side of the wall's circumference and so about is about mid-way from the nearest (e.g., second end's) flange.

The second embodiment of the clamp assembly is also referred to as the “A2 Grunt loop”, and since it is configured to easily and quickly attach to an M16A2 stock, it is also configured for easy use upon aftermarket buttstock assemblies or “back ends” such as a MAGPUL® aftermarket stock assembly.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of a specific embodiment thereof, particularly when taken in conjunction with the accompanying drawings, wherein like reference numerals in the various figures are utilized to designate like components.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a CAR-15 style rifle with a single point sling attachment, as seen in the prior art.

FIG. 2 illustrates a single point sling, as seen in the prior art.

FIG. 3 illustrates a hook with a spring-biased safety catch or lever, as seen in the prior art.

FIG. 4 illustrates a quick-detachable (QD) style sling attachment, as seen in the prior art.

FIG. 5A is a perspective view of a first embodiment of the loop-shaped clamping member of the present invention.

FIG. 5B is a boss-side or left side view in elevation of a first embodiment of the loop-shaped clamping member of FIG. 5A, in accordance with the present invention.

FIG. 5C is an axial end view in elevation of the loop-shaped clamping member of FIGS. 5A and 5B, in accordance with the present invention.

FIG. 5D is a right side view in elevation of the loop-shaped clamping member of FIGS. 5A, 5B and 5C, in accordance with present invention.

FIG. 5E is a side view in elevation of the socket cap screw threaded fastener for use with the loop-shaped clamping member of FIGS. 5A, 5B and 5C, in accordance with present invention.

FIG. 6 illustrates an exploded view of the loop-shaped clamping member of the present invention aligned on the central axis of a buffer tube in preparation for adjusting the loop shaped clamping member on a CAR-15 style rifle to provide an adjustable single point sling attachment.

FIG. 7 illustrates a side view, in elevation, of the loop-shaped clamping member of FIG. 6, when aligned on the central axis of a buffer tube and adjusted to provide an adjustable single point sling attachment.

FIG. 8 illustrates a top view, in elevation, of the loop-shaped clamping member of FIGS. 6 and 7, when aligned on the central axis of a buffer tube and adjusted to provide an adjustable single point sling attachment.

FIGS. 9A and 9B are perspective views of a second embodiment of the loop-shaped clamping member, configured for use on the butt-stock of a M16A2, in accordance with the present invention.

FIG. 9C is a cross sectional, axial view in elevation of the loop-shaped clamping member of FIGS. 9A and 9B, in accordance with the present invention.

FIG. 9D is a top side view in elevation of the loop-shaped clamping member of FIGS. 9A, 9B and 9C, in accordance with the present invention.

FIG. 9E is a side view in elevation of the cap screw threaded fastener for use with the loop-shaped clamping member of FIGS. 9A, 9B and 9C, in accordance with present invention.

FIG. 9F is an axial end view in elevation of the loop-shaped clamping member of FIGS. 9A, 9B and 9C, in accordance with the present invention.

FIG. 9G is a another top side view in elevation of the loop-shaped clamping member of FIGS. 9A, 9B and 9C, showing the transversely projecting boss, in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to FIGS. 1-9G, a loop-shaped clamping member 200 is illustrated in several views. Loop-shaped clamping member 200 is configured with a transversely projecting boss member 210 which has an aperture 222 therethrough to provide an ideal sling attachment point. A sling such as sling 108 with latching hook 110 as illustrated in FIGS. 2 and 3 is preferred. Boss aperture 222 provides a substantially circular through-bore whose diameter is approximately 0.25″ with chamfered edges at both ends of the through bore, and so provides a snag-free, essentially cylindrical lumen to receive and engage latching hook 110 and to provide a durable and trouble-free sling connection.

As noted above, vertically slotted sling connection points as used in the prior art give rise to twisted slings and make the rifle (e.g. 100) awkward to handle.

The loop-shaped clamping member's transversely projecting connection point or boss 210 is horizontal and so allows a single point sling 108 to hang naturally without a partial twist in the sling.

Loop-shaped clamping member 200 is also referred to as the “Grunt loop”, and since it is configured to easily and quickly attach to an M4 stock assembly's buffer tube, it is also configured for easy use upon aftermarket CAR15 or M4 compatible buttstock assemblies or “back ends” such as a MAGPUL® aftermarket stock assembly.

The loop-shaped clamping member 200 is configured as a substantially cylindrical spring clamp-like assembly made from a strip of spring steel (or spring-steel like (e.g., 17-4) stainless steel) which is fabricated to be biased in the closed or clamped position (as shown in FIGS. 5A and 5C, such that a first clamp end 230 is proximate to or abuts a second clamp end 240 when loop-shaped clamping member 200 is at rest, whether on or off the rifle.

Loop-shaped clamping member 200, when in the normal, closed position defines a cylinder having a central axis 250 and an axial wall 260 with a cylindrical wall height of 0.388 inches and an interior lumen diameter of 1.345 inches. The sidewall thickness of the clamping member is, for most of its length, 35 thousandths (0.035″). Alternatively, applicant has made loops with parts the O.D. run at 1.396 inches (tolerance + or −0.005 inches) to achieve a wall thickness of 0.025″ In other prototypes, it was discovered that grunt loops made with a 0.017 wall thickness were too flimsy and could not readily be made to look smooth. The cross section of wall 260 is optionally tapered to be thinner at the edges and (preferably) an added 0.050″ edge radius is applied to the edges of the cylindrical wall and to the sling attachment. As a practical matter for the machinist, the thickness of these parts will always be dependent on the thickness of the ⅜ plate stock used in fabricating. Sometimes that plate stock is its right at 0.375″ but sometimes the plate stock thickness is closer to 0.390″ so the finished thickness is a function of the materials used.

Referring to FIGS. 5A-5E, clamp first end 230 is configured with a first transversely projecting flange 232 to receive and engage a threaded fastener 220 in a first fastener receiving bore 234. The first end flange's bore 234 is aligned along a fastener axis which is orthogonal to the central axis 250 of the clamp loop, so that threaded bolt or socket cap screw 220 can be inserted into and through bore 232 in the first end flange 230 and threadably engaged in the second flange's bore 242, to approximate and fasten the clamp ends together.

The first flange bore 232 is preferably relieved with a larger counter bore to completely receive and conceal the head of fastener 220, so that fastener 220 cannot snag any part of the sling, when carried in the field.

Clamp end 240 is configured with a transversely projecting flange 242 to receive and engage threaded fastener 220 in second fastener receiving bore 244. Second flange 240 preferably has its bore interior threaded with #10-32 threads, to engage the threads on fastener 220. As noted above, first end flange bore 234 is aligned with the second end flange's bore 244 along the fastener axis which is orthogonal to clamp central axis 250, so that when threaded bolt or screw 220 is inserted into and through bore 234 in the first end flange and be threadably engaged in bore 244 of the second end flange, and fastener 220 can be threadably advanced or tightened using a screw driver or Allen™ key style tool to approximate and fasten the clamp ends together.

When viewing the clamp assembly 200 from the perspective of the loop-shaped clamp's major central axis (as shown in FIG. 5C), with the first end 230 and second end 240 at the bottom, the transversely projecting boss 210 projects in a substantially horizontal direction, meaning that the transverse (sling receiving) boss 210 projects outwardly from the clamp's exterior wall 260 at an azimuth which is 90 degrees or one quarter of the wall's circumference from the nearest (e.g., second end 240) flange.

In use, loop-shaped clamping member 200 is configured to work well with an HK style hook (e.g., such as hook 110, with a spring biased safety catch or lever) because loop-shaped clamping member 200 orients the user's movements in a single direction of when releasing sling hook 110. In a life-threatening situation, it is easy to depress and release a snapped hook 110 from the loop-shaped clamping member's attachment boss 210. Loop-shaped clamping member 200 is readily adjusted for use in a variety of positions. For example, a right-handed user can selectively loosen fastener 220, and axially rotate the clamp assembly 200 so that transversely projecting boss attachment 210 swings around the axis 250 to a selected angular orientation between 7 to 10 o'clock (e.g., when viewed from the butt end of rifle 100), and then re-tightening fastener 220.

Rotation of loop-shaped clamping member 200 around the central axis the buffer tube locking nut allows the user to select an angular orientation for the sling attachment which helps balance the side-to-side rotation of the rifle with an infinitely adjustable arc of rotation. This allows the right hand shooter to adjust the position of the clamp assembly or Loop 200 to fit his or her carrying style and accessory outfit (i.e., of the rifle, configured or mounted accessories might include a flashlight, an IR laser, a forward hand grip, or a bipod, etc.—all of which change the balance of the rifle by adding weight at different points). Applicant knows of no other single point connection which is rotationally adjustable—all have a fixed point and all have a right and left hand connection. The loop 200 is shooter (side) adjustable to be left-hand or right-hand specific (because loop 200 can be changed from side to side so easily—if needed) for adjustability of the rifle's rotational balance.

A Left-handed shooter would put loop-shaped clamping member 200 onto the rifle with the opposing back-to-front orientation (or backwards) in order to accommodate left hand use with the same rotational adjustability, where now a desired angular orientation is likely to be between 2 to 5 O'clock, with attachment boss 210 projecting laterally to the right side of the rifle, when viewed from the buttstock's proximal end).

The fact that the Grunt Loop 200 utilizes a horizontal connection (not a vertical slot) also helps to dampen the rifle rotation when the user is moving (because the sling attachment or hook does slide laterally within a slot (such as slot 14 in prior art single point connection of Published application 2005/0034347, to Verdugo).

Since the clamp assembly or loop 200 of the present invention is configured as a spring clamp which is based closed, there is no need to loosen the buffer tube locking nut (which requires a specialized tool), or disassemble the buffer tube assembly. Instead, loop-shaped clamping member 200 allows the user to entirely avoid the process of taking apart the buffer tube assembly when mounting or adjusting a single point sling mount. Loop-shaped clamping member 200 is flexible, tough and ductile enough to permit significant spreading at the loop opening (when Clamping Screw 220 is removed), and can be deformed or spread to separate first flange 232 apart from second flange 242 far enough to pass around a standard buffer tube assembly's cylindrical sidewall.

When being installed, loop-shaped clamping member 200 is unfastened and is simply spread apart and slipped over the buffer tube/locking nut ring without ever removing anything from the rifle's butt assembly.

Preferably, when making loop 200, either 316 or 17-4 stainless alloy is anodized black or an earth tone color. Loop-shaped clamping member 200 can be installed and removed, adjusted and readjusted literally hundreds of times without fear of failure. It can be installed (if an Allen wrench is close at hand) in less than one minute, and is designed for a collapsible AR stock (CAR) or where any buffer tube and/or buffer tube locking nut or butt extension are exposed (e.g., on a different style of rifle such as the Tubb 2000™ rifle).

Another method of installation (though more time consuming) is accomplished by pulling out on the CAR length adjustment lever arm (normally the lever is compressed to select the length position setting) and sliding the plastic butt assemble off of the buffer tube, as shown in FIG. 6. This allows one to install the loop-shaped clamping member 200 by simply spreading the loop (not as much as when snapping over the buffer locking nut by itself) and then sliding it down the length of the buffer tube and over the buffer tube-locking nut into mounting position 103. Next, the user preferably orients or adjusts the loop-shaped clamping member's boss' horizontal connection hole 222 to the user's desired position and tightens it in place (e.g., with the Allen wrench). An AR15/M16's charging handle remains unobstructed and operable with loop-shaped clamping member 200 in place and positioned appropriately.

For standard production, loop-shaped clamping member 200 is preferably machined from a stainless steel alloy such as 17-4 Stainless Steel. For corrosive environments (saltwater) loop-shaped clamping member 200 can optionally be made from 316L Stainless Steel, with a Stainless Steel clamping cap screw 220. Alternatively, the loop 200 can be fabricated from a tough aluminum alloy such as 7075-T6 aluminum alloy.

In general terms sling support loop 200 is a sling fitting for firearm 100 comprising a fitting body, with an axial sidewall terminating in proximal and distal sidewall ends, having a main aperture or interior lumen having a central axis 250 which is axially aligned with the buffer tube assembly's central axis and parallel to the central axis of the rifle's barrel. The sling support loop 200 carries a transverse projection or boss 210 that projects laterally or radially away from the main loop's sidewall 260 and has an aperture or bore 222 with a central axis that is perpendicular to the main aperture's central axis 250. The transverse projection's aperture is configured to receive a releasable sling attachment such as hook 110. The transverse hook-receiving attachment bore 222 is radially displaced from the main interior lumen and defines the sling fitting for attachment of a sling system (e.g., 108) to the weapon, where the attachment bore is preferably chamfered at the bore's first and second open ends and is configured to releasably accommodate a sling in a way which minimizes the likelihood of binding the sling clamp in a given position.

The support loop's main aperture is configured as a radially adjustable clamp with an open-loop shaped body and so is configured to be releasably mounted upon the firearm at a selected radial or angular orientation, and the firearm is then configured to hang from the sling in a selected vertical orientation, so the user can readily grasp the weapon and bring it into a ready or aiming position.

Loop or clamp assembly 200 (as shown in FIGS. 5A-8) comprises cylindrical sidewall 260, terminating flanges 232, 242, and transversely projecting boss 210 which are forged or welded into single piece, to provide a unitary, integral, one-piece clamp assembly configured as a spring clamp that is spring biased in the closed position, to define a substantially continuous loop around axis 250. The only separable or removable part of clamp assembly 200 is threaded fastener 220.

It will be appreciated by those having skill in the art that the method of the present invention has driven the requirements of the structure described above; specifically, the method for adjusting the angular orientation of sling attachment clamp 200 to a rifle with a proximally projecting buffer tube assembly, includes providing a loop 200 selected to be clamped tightly around the exterior surface of the weapon's proximally projecting tubular member having a first sidewall end which is spring-biased to abut a second end sidewall end (230 and 240) for mounting loop 200 upon the firearm at a selected radial orientation. Next, the user opens and spreads the first end 230 apart from the second end 240 to define a sidewall gap or opening large enough to go around the exterior of the rifle's buffer tube and, next, the user can place the loop 200 over the exterior surface of the rifle's proximally projecting buffer tube via the loop's sidewall gap or opening so that said loop-shaped body springs back to a closed position and encircles the exterior of the rifle's buffer tube. Next, the user selects a desired angular orientation for loop 200 upon the rifle's buffer tube (e.g., with the transverse boss 210 projecting radially away from the buffer tube's central axis in a desired orientation (e.g., left or right). The transverse boss' selected angular orientation is infinitely adjustable over a 360 degree sweep, and once the desired angular orientation is found, the user can clamp the ends together using faster 220. Next, the user hangs the weapon from his or her left or right shoulder (or other body appendage) to learn whether the resulting, selected hanging vertical orientation allows the user to readily grasp the weapon and bring it into a ready or aiming position. If needed, after seeing how the weapon hangs from the single point sling attachment 200, the user can fine-tune or adjust the loop's angular orientation (e.g., clockwise or counterclockwise, as seen from the rifle's proximal end).

Another embodiment for use with the M16A2 is illustrated in FIGS. 9A-9F, where the second oval loop-shaped clamping member 400, configured for use on the butt-stock of a M16A2. The oval loop-shaped clamping member 400 is also configured as an asymmetrical elliptic cylinder-shaped spring clamp-like assembly made from a strip of resilient, tough metal such as an aluminum alloy (e.g., 7075-T6 aluminum alloy). Alternatively, loop 400 can be fabricated from spring steel (or spring-steel-like (e.g., 17-4) stainless steel) which is biased in the closed or clamped position, such that a first clamp end 430 is proximate to or abuts a second clamp end 440 when clamping member 400 is at rest, on or off the rifle.

Oval clamping member 400, when in the normal, closed position (as shown in FIGS. 9A-9D defines an asymmetrical elliptic cylinder having an offset central axis 450 and an axial wall height of 0.375 inches and an interior lumen shaped to encircle and tightly hold the outer peripheral wall of an M16's buttstock, at the narrow front end, proximate the receiver. The sidewall thickness of the clamping member is, for most of its length, 50 thousandths (0.050″).

Each of the clamp ends 430, 440 is configured with a transversely projecting flange 432, 442 to receive and engage a threaded fastener 420 in first and second fastener receiving bores 434, 444. The first end flange's bore 434 is aligned with the second end flange's bore 444 along a fastener axis which is orthogonal to the central axis 450 of the clamp, so that when threaded bolt or screw 420 is inserted into and through bore 434 in the first end flange can be threadably engaged in bore 444 of the second end flange, to approximate and fasten the clamp ends together. When viewing clamp assembly 400 from the perspective of the loop-shaped clamp assembly's central axis 450 (as in FIG. 9F), with the first end 430 and second end 440 on the left side, the transversely projecting boss 410 projects in a substantially opposing lateral direction, on the right side, meaning that the transverse (sling receiving) boss 410 projects outwardly from the clamp's exterior wall 460 at an azimuth which is nearly on the opposite side of the wall's circumference and so about is about mid-way from the nearest (e.g., second end's) flange 442.

For the Loop or clamp assembly 400, as shown in FIGS. 9A-9G, the cylindrical sidewall 460, terminating flanges 432, 442 and transversely projecting boss 410 are of a single piece, forged or welded together, to provide a unitary, integral, one-piece clamp assembly configured as a spring clamp that is spring biased in the closed position, to define a substantially continuous loop. The only separable or removable part of clamp assembly 400 is the threaded fastener 420.

Clamp assembly 400 is also referred to as the “A2 Grunt loop”, and since it is configured to easily and quickly attach to an M16A2 stock, it is also configured for easy use upon aftermarket buttstock assemblies or “back ends” such as a MAGPUL® aftermarket stock assembly.

It will also be appreciated by those having skill in the art that the method of the present invention has driven the requirements of the structure for oval loop 400 described above; specifically, the method for attaching sling attachment clamp 400 to a rifle with a proximally projecting buttstock assembly (such as a M16A2), includes providing a loop 400 selected to be clamped tightly around the exterior surface of the weapon's proximally projecting buttstock assembly having a first sidewall end which is spring-biased to abut a second end sidewall end (e.g., 430 and 440) for mounting loop 400 upon the firearm at a selected location (e.g., near the proximal end of the upper receiver).

Next, the user opens and spreads the first end 430 apart from the second end 440 to define a sidewall gap or opening large enough to go around the exterior of the rifle's buttstock assembly and next the user places the loop 400 over the exterior surface of the rifle's proximally projecting buttstock assembly via the sidewall gap or opening so that said loop-shaped body springs back to a closed position and encircles the exterior of the rifle's buttstock assembly. Next, the user selects a desired angular orientation for said loop 200 upon the rifle's buttstock assembly (e.g., with the transverse boss 410 projecting radially away from the buffer tube's central axis 450 in a desired orientation (e.g., left or right).

Next, the user hangs the weapon from his or her left or right shoulder (or other appendage) to learn whether the resulting, selected hanging vertical orientation allows the user to readily grasp the weapon and bring it into a ready or aiming position.

Having described and illustrated preferred embodiments of a new and improved sling support loop and method, it is believed that other modifications, variations and changes will be suggested to those skilled in the art in view of the teachings set forth herein. It is therefore to be understood that all such variations, modifications and changes are believed to fall within the scope of the present invention. 

1. A sling adapter for a weapon or firearm such as an M4 Carbine having a substantially tubular proximally projecting member, comprising: (a) first open loop-shaped body with a substantially tubular sidewall terminating in proximal and distal edges and defining a main interior lumen having a center within an interior diameter selected to be clamped tightly around the exterior surface of the weapon's proximally projecting tubular member; (b) wherein said loop-shaped body's tubular sidewall carries a transversely projecting boss, and wherein said transversely projecting boss defines a sling-fastener receiving attachment bore radially displaced from the main interior lumen and defining the sling fitting for attachment of a sling system to the weapon, the attachment bore being configured to releasably accommodate a sling-fastener; (c) wherein the loop-shaped body's main aperture is configured as a radially adjustable clamp for mounting said body upon the firearm at a selected radial orientation, and wherein said weapon is then configured to hang at a selected vertical orientation, so the user can readily grasp the weapon and bring it into a ready or aiming position.
 2. The sling adapter of claim 1, wherein said loop-shaped body and transversely projecting boss are fabricated in a one-piece, unitary spring clamp from a resilient metal.
 3. The sling adapter of claim 2, wherein said loop-shaped body and transversely projecting boss are fabricated from a stainless steel alloy.
 4. The sling adapter of claim 3, wherein said loop-shaped body and transversely projecting boss are fabricated from 17-4 stainless steel alloy.
 5. The sling adapter of claim 2, wherein said loop-shaped body and transversely projecting boss are fabricated from spring steel.
 6. The sling adapter of claim 2, wherein said loop-shaped body and transversely projecting boss are fabricated from aluminum.
 7. The sling adapter of claim 2, wherein said loop-shaped body and transversely projecting boss are fabricated from 7075-T6 aluminum alloy.
 8. A releasable and user-adjustable sling attachment for a firearm, comprising: a loop-shaped clamping member configured as a substantially cylindrical spring clamp-like assembly made from a strip of resilient, tough material fabricated to be biased in the closed or clamped position, such that a first clamp end is proximate to or abuts a second clamp end when the loop-shaped clamping member of the present invention is at rest; wherein said loop-shaped clamping member, when in the normal, closed position defines a cylinder having a central axis and an axial wall with an interior lumen, and wherein each of said clamp ends is configured with a transversely projecting flange to receive and engage a threaded fastener in first and second fastener receiving bores; wherein said first end flange's bore is aligned with the second end flange's bore along a fastener axis which is orthogonal to the central axis of the clamp, so that a threaded bolt or screw may be inserted into and through the bore in the first end flange and threadably engaged in the bore of the second end flange, to approximate and fasten the clamp ends together; and wherein said transversely projecting boss projects outwardly from the clamp's exterior wall at an azimuth which is approximately one quarter of the wall's circumference from the nearest end's flange.
 9. The releasable and user-adjustable sling attachment of claim 8, wherein said loop-shaped clamping member wall and transversely projecting boss are fabricated into a one-piece, unitary clamp from a resilient metal.
 10. The sling adapter of claim 9, wherein said loop-shaped clamping member wall and transversely projecting boss are fabricated from a stainless steel alloy.
 11. The sling adapter of claim 10, wherein said loop-shaped clamping member wall and transversely projecting boss are fabricated from 17-4 stainless steel alloy.
 12. The sling adapter of claim 9, wherein said loop-shaped clamping member wall and transversely projecting boss are fabricated from spring steel.
 13. The sling adapter of claim 9, wherein said loop-shaped clamping member wall and transversely projecting boss are fabricated from aluminum.
 14. The sling adapter of claim 13, wherein said loop-shaped clamping member wall and transversely projecting boss are fabricated from 7075-T6 aluminum alloy.
 15. A method for adjusting the angular orientation of a sling attachment clamp to a rifle with a proximally projecting buttstock or buffer tube assembly, comprising the method steps of: (a) providing a first open loop-shaped body with a substantially tubular sidewall terminating in proximal and distal edges and defining a main interior lumen having a center within an interior diameter selected to be clamped tightly around the exterior surface of the weapon's proximally projecting tubular member; wherein said loop-shaped body's tubular sidewall carries a transversely projecting boss, and wherein said transversely projecting boss defines a sling-fastener receiving attachment bore radially displaced from the main interior lumen and defining the sling fitting for attachment of a sling system to the weapon, the attachment bore being configured to releasably accommodate a sling-fastener, and wherein the loop-shaped body's main aperture is configured as a radially adjustable clamp having a first sidewall end which is spring-biased to abut a second end sidewall for mounting said body upon the firearm at a selected radial orientation; (b) opening and spreading said sidewall's first end apart from said sidewall's second end to define an sidewall gap or opening large enough to go around the exterior of the rifle's buffer tube or stock; and (c) placing said loop-shaped body over the exterior surface of the rifle's proximally projecting stock or buffer tube via the sidewall gap or opening so that said loop shaped body springs back to a closed position and encircles the exterior of the rifle's buffer tube or stock.
 16. The method for adjusting the angular orientation of a sling attachment clamp to a rifle of claim 15, further comprising the method step of: (d) selecting a desired angular orientation for said loop-shaped body upon said rifle's buffer tube or stock.
 17. The method for adjusting the angular orientation of a sling attachment clamp to a rifle of claim 16, further comprising the method step of: (e) hanging said weapon a resulting, selected vertical orientation, so the user can readily grasp the weapon and bring it into a ready or aiming position. 